1. Field of the Invention
The disclosure relates generally to computer systems and, more specifically, to a computer system and device for increasing bandwidth between a blade server and other devices within the computer system.
2. Description of the Related Art
FIG. 1 illustrates a system 200 for packaging a computer system. The computer system may include multiple blade servers 202, a first (top) set of devices 204, a second (bottom) set of devices 206, and a midplane 270. In addition, the computer system may includes blowers 207 and 209. The system 200 includes a main chassis 250 and a SPC chassis 260. The main chassis 250 includes a first cavity 210 and a second cavity 212. The first cavity 210 is configured to receive the blade servers 202, as well as a peripheral device 208. Additionally, the main chassis 250 may be configured such that each of the blade servers 202 is hot pluggable into the first cavity 210.
The SPC chassis 260 may be configured to retain the modules for the devices 204 and 206. In certain aspects, the devices 204 and 206 are hot pluggable into the SPC chassis 260. In addition, the SPC chassis 260 may be configured to plug into the main chassis 250. In particular, the SPC chassis 260 can be retained in the second cavity 212 of the main chassis 250. A common plenum 240 may be positioned between the modules for the devices 204 and 206 and between the blowers 207 and 209. The first plenum 220 may be formed above the SPC chassis 260 and between the SPC 260 chassis and the main chassis 250. The lower plenum 230 may be formed below the SPC chassis 260 and between the SPC chassis 260 and the main chassis 250.
The midplane 270 may be a printed circuit board to which the blade servers 202 and devices 204 and 206 connect. In addition, the midplane 270 includes apertures 276 in a central portion of the midplane 270. The apertures 276 in the midplane 270 provide a path for air from the blade servers 202 to the common central plenum 240. In addition, when in place, apertures 272 and 274 are formed between the main chassis 250 and the midplane 270. The apertures 272 and 274 provide a path for air from the blade servers 202 to the upper plenum 220 and lower plenum 230, respectively. Due to the arrangement of the plenum 220, 230 and 240, as well as the placement of the blade servers 202 and the devices 204 and 206, higher density packing of the blade servers 202 is possible while meeting the cooling requirements of the blade servers 202, devices 204, and devices 206.
FIGS. 2A and 2B respectively illustrate a conventional midplane 270 and blade server 202. The blade server 202 typically uses a pair of plugs 258 that plug into connectors 280 on the midplane 270. In conventional systems, only these interconnects 258, 280 are used to connect the blade server 202 to the midplane 270. As a result, all possible interconnections must be included in the midplane 270 to allow for flexibility in meeting the demands of differing applications. However, configuring the connectors 280 of the midplane 270 to meet all possible demands adds cost and complexity to the midplane 270. As a result, it can be economically undesirable to build additional functionality into the midplane 270 that is infrequently used.
Another issue associated with the conventional interconnects 258, 280 between a blade server 202 and midplane 270 is the continual need to increase the bandwidth between the interconnects 258, 280. Increasing the bandwidth typically involves increasing the number of wires per link and/or increasing the link speed of each wire. However, in many situations, a particular wire is already operating at a maximum operational datarate. In these instances, the only option is to increase the number of wires.
Issues are also associated with increasing the number of wires in the interconnects 258, 280. Adding wires/pins to the interconnects 258, 280 increases the complexity and cost of the midplane 270 itself since the additional wires from the interconnects 258, 280 requires additional and more complex wiring layers within the midplane 270, which is itself a circuit board., and exponentially increases the cost of the board. For example, to upgrade from a 1 Gb interconnect to a 10 Gb interconnect increases the number of wires for a single communication path from 4 to 16, which is a 4× increase in number of wires.
As illustrated in FIG. 1, if the midplane 270 is a shared midplane 270 such that the midplane 270 connects to blade servers 202 on one side and devices 204, 206 on the other side, the problem of additional bandwidth is exacerbated. The thickness of the shared midplane 270 is a critical component in ensuring the proper mechanical positioning and connection between the midplane 270 and both the blade servers 202 and devices 204, 206. Thus, to increase the thickness of the midplane 270 to accommodate additional wires for the increased bandwidth may require a redesign of many of the components within the system 200 to maintain proper spacing between the components.
Yet another issue associated with modifying the shared midplane 270 to accommodate increased bandwidth is to maintain the airflow through the apertures 276 of the midplane 270. Although increasing the surface area of the midplane 270 may increase the capability of the midplane 270 to accommodate additional wires, this modification of the midplane 270 would decrease the area of the apertures 276, which could result in insufficient airflow through the midplane 270 and through the system 200. There is, therefore, a need for a system and device for increasing the bandwidth between a blade server and other devices within the computer system without substantially increasing the complexity of the midplane or interfering with airflow through the midplane.